Partitions for Mac and PC

Question

Partitions for Mac and PC

I have a G4 PowerBook running 10.5.8 and also have a Windows laptop. I have an external hard drive that I would like to use for both the Mac and the PC.

I have split the external drive into 3 partitions. One for my Mac clone, one for Time Machine and one to back up the PC. The problem is that when I set the Format type to Apple Partition Map, it applies it to all 3 partitions and I can't partition the third partition to FAT. When I plug the disk into the Windows PC, the computer recognized the hardware but I cannot see the partition in Windows Explorer.

If I start off my making all three partitions FAT and then reformat the 2 Mac partitions to OX S Extended Journaled, I get a message from Carbon Copy Cloner that the disk will not be bootable because a Power PC need Apple Partition Map.

Isn't the whole point of making separate partitions that they can be different formats and be used on different machines/platforms?

I suspect I am missing something simple here as there must be a way to do this.

Anny advice would be appreciated.

Thanks,

David

13" MacBook Pro & G5 iMac Rev. B., Mac OS X (10.6.1)

Posted on Oct 30, 2009 7:45 PM

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Answer 1

V.K.

Level 9

56,174 points

Oct 30, 2009 8:07 PM in response to David Schwartzer

you should be able to format a partition FAT when the whole drive is formatted with Apple Partition Map. I don't know why you can't do it. you might need to reformat the whole drive again but this should certainly be possible.

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Answer 2

Oct 30, 2009 10:31 PM in response to David Schwartzer

Drives have two part to formatting. The first is a partition map, the second is partitions. This map tells the computer where the partitions are, and information about those partitions.

Apple Partition Map (APM for short) is needed to boot a power pc computer. This has to do with the code on the logic board called Open Firmware. Open Firmware Only knows how to read APM partitioning. Witch means it can only load the OS from an APM partitioned drive.
The reason Disk Utility will not let you set a DOS on a partition is that APM is not not compatible with DOS formatting.

FYI:

Disk utility will also let you set the partition map to MBR (dos) but again the Open Firmware will not read MBR.

You can also set the partitioning to GPT. GPT, also known as GUID Partitionin, is the ideal Partition map for intel based mac. This is because intel macs use EFI instead of Open Firmware. GUID will let you have DOS,NTF, and Mac OS Extended partitions. But a power PC computer will not boot off of GUID.

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Answer 3

jsd2

Level 5

6,245 points

Oct 30, 2009 10:33 PM in response to V.K.

I don't know why, but I am also not offered FAT32 as a volume format choice under an APM partition scheme. What I see for volume choices just after newly partitioning a test USB flash drive are:

APM
!http://i34.tinypic.com/332xoop.jpg!

GUID and MBR
!http://i38.tinypic.com/2yxpso0.jpg!

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Answer 4

Oct 30, 2009 10:55 PM in response to jsd2

you need to set it up when your partitioning the drive.

click on the drive, click on the tab partition set the volume scheme to 2 partitions, click on one of the partitions and chose dos. click apply. this will destroy all data on the drive.

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Answer 5

Oct 30, 2009 11:05 PM in response to Sherman Campbell

It has been my experiences that if you set a dos partition on a MBR drive window fails to recognize the drive as being formatted.

you can set the partition map to MBR. Windows will recognize a dos partition on a MBR drive. You can also add a Mac OS Extended partition. Witch will let you use time machine to back up the computer. Of corse you can't boot to a time machine back up.

But there is an advantage. I can restore the computer to how it was on multiple days.

Is there a reason you can't transfer the files over your local network?

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Answer 6

jsd2

Level 5

6,245 points

Oct 31, 2009 3:26 AM in response to Sherman Campbell

you need to set it up when your partitioning the drive.

click on the drive, click on the tab partition set the volume scheme to 2 partitions, click on one of the partitions and chose dos. click apply. this will destroy all data on the drive.

This still does not work if I have first chosen Apple Partition Map using the Options button.
Even at the time of partitioning with the Partitions tab, I am offered the choice of MS-DOS (FAT) as a volume format only if I have chosen GUID or MBR under "Options", and not if I have chosen Apple Partition Map.

APM:
!http://i37.tinypic.com/1z3rvnm.jpg!
.
.
GUID and MBR:
!http://i34.tinypic.com/16iuv7k.jpg!

.
Do you see something different for volume choices after you choose APM as the partition scheme using the "Options" button? You can first look at the volume choices available within the Partition tab under various partition scheme options without finally clicking the Apply button, so you don't have to actually erase anything.

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Answer 7

jsd2

Level 5

6,245 points

Oct 31, 2009 7:36 AM in response to jsd2

David,

I have split the external drive into 3 partitions. One for my Mac clone, one for Time Machine and one to back up the PC. The problem is that when I set the Format type to Apple Partition Map, it applies it to all 3 partitions and I can't partition the third partition to FAT. When I plug the disk into the Windows PC, the computer recognized the hardware but I cannot see the partition in Windows Explorer.

I get the same format limitation with Apple Partition Map, as above.

Since you need APM if you want your PPC clone to be bootable, your best bet might be to install [MacDrive|http://www.mediafour.com/products/macdrive> on your Windows machine. I don't run Windows and I don't know how well this works in practice.

You could instead use an MBR partition scheme and create one FAT32 partition for Windows and the other two formatted for Mac, accepting the limitation that the G4 clone partition would not then be bootable. A clone doesn't have to be bootable to still be useable - you could still restore from it after a crash it by booting from your install disk, running Disk Utility from there, and using DU's Restore tab with the clone as source. You can't readily test a non-bootable clone, though, and I think this is a lot less desirable.

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Answer 8

V.K.

Level 9

56,174 points

Oct 31, 2009 8:29 AM in response to jsd2

this is strange. I first tried it on my snow leopard install and it does let me create a FAT partition when formatting a drive with APM. but then I did it on my leopard machine and disk utility there DOES NOT give that option and I see the same choices only as you do in that screenshot. a bug in leopard disk utility? I'm not sure. you can try formatting the drive from command line using "diskutil" but I don't have a spare drive to actually do it and see if it works or not.

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Answer 9

jsd2

Level 5

6,245 points

Oct 31, 2009 9:45 AM in response to V.K.

I have a G5 and can't run Snow Leopard. I just rebooted into Tiger, and Disk Utility there offered an additional volume format option called "Unix File System" for all three partition schemes, which I did not see in Leopard. However "MS-DOS File System" was still only offered for MBR and GUID and not for APM.

It would be interesting to know if Windows can actually read the FAT32 volume that Snow Leopard creates on an APM drive. I just found this:
[FAT32 External HDD formated with Mac OS not mountable on a Windows machine|http://superuser.com/questions/49068/fat32-external-hdd-formated-with-m ac-os-not-mountable-on-a-windows-machine]

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Answer 10

baltwo

Level 9

62,362 points

Oct 31, 2009 11:28 AM in response to jsd2

See Create an HFS+/NTFS/FAT32 external drive

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Answer 11

V.K.

Level 9

56,174 points

Oct 31, 2009 12:05 PM in response to jsd2

jsd2 wrote:
I have a G5 and can't run Snow Leopard. I just rebooted into Tiger, and Disk Utility there offered an additional volume format option called "Unix File System" for all three partition schemes, which I did not see in Leopard. However "MS-DOS File System" was still only offered for MBR and GUID and not for APM.

It would be interesting to know if Windows can actually read the FAT32 volume that Snow Leopard creates on an APM drive. I just found this:
[FAT32 External HDD formated with Mac OS not mountable on a Windows machine| http://superuser.com/questions/49068/fat32-external-hdd-formated-with-mac-os-not -mountable-on-a-windows-machine ]

I just cleared the data on one of my externals and tried formatting it in various ways from my snow leopard machine. first I partitioned it APM with two partitions: one HFS and one FAT. then I rebooted into windows. Windows did not see either of the partitions. then I booted back into snow leopard and reformatted it using APM. then I booted into windows and it saw both partitions (I have snow leopard drivers installed in bootcamp so it can read HFS+). so there may be something to that link. the method in baltwo's link might be your best option.

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Answer 12

jsd2

Level 5

6,245 points

Oct 31, 2009 12:27 PM in response to V.K.

tried formatting it in various ways from my snow leopard machine. first I partitioned it APM with two partitions: one HFS and one FAT. then I rebooted into windows. Windows did not see either of the partitions

then I booted back into snow leopard and reformatted it using APM. then I booted into windows and it saw both partitions

I'm not clear what you did differently the second time-- could you explain further?

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Answer 13

V.K.

Level 9

56,174 points

Oct 31, 2009 1:36 PM in response to jsd2

jsd2 wrote:

tried formatting it in various ways from my snow leopard machine. first I partitioned it APM with two partitions: one HFS and one FAT. then I rebooted into windows. Windows did not see either of the partitions

then I booted back into snow leopard and reformatted it using APM. then I booted into windows and it saw both partitions

I'm not clear what you did differently the second time-- could you explain further?

oops, that was a misprint, sorry. the second time I formatted it using GUID partition scheme. then windows saw both partitions without any issues.

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Answer 14

jsd2

Level 5

6,245 points

Oct 31, 2009 2:06 PM in response to V.K.

Ah.. thanks. It seems as if Snow Leopard might be the system with the bug for allowing FAT32 on an APM drive, rather than Leopard or Tiger!

I'm not the OP, but his question was essentially "Can the same external drive have one partition is readable by Windows, and another partition that will boot a PPC mac?"
The answer seems to be no - not without using something like [MacDrive|http://www.mediafour.com/products/macdrive], which is what I had suggested earlier. Is this a good product?

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Answer 15

V.K.

Level 9

56,174 points

Oct 31, 2009 2:28 PM in response to jsd2

jsd2 wrote:
Ah.. thanks. It seems as if Snow Leopard might be the system with the bug for allowing FAT32 on an APM drive, rather than Leopard or Tiger!

well, I wouldn't necessarily draw that conclusion just yet. after all, there could be a problem with my SL install, the external hard drive, or the my windows install. but this is what happened to me.

I'm not the OP, but his question was essentially "Can the same external drive have one partition is readable by Windows, and another partition that will boot a PPC mac?"
The answer seems to be no - not without using something like [MacDrive| http://www.mediafour.com/products/macdrive ], which is what I had suggested earlier. Is this a good product?

I don't use it as it's pretty expensive and I rarely have a need to write to my mac partition from windows. new Snow leopard bootcamp drivers make HFS+ drives readable from windows and that's good enough for me. but it's an option for people who do need to write to OS X partition from bootcamp.

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